# Copyright (c) OpenMMLab. All rights reserved.
from mmcv.transforms import RandomChoice, RandomChoiceResize
from mmcv.transforms.loading import LoadImageFromFile
from mmengine.config import read_base
from mmengine.model.weight_init import PretrainedInit
from mmengine.optim.optimizer.optimizer_wrapper import OptimWrapper
from mmengine.optim.scheduler.lr_scheduler import MultiStepLR
from mmengine.runner.loops import EpochBasedTrainLoop, TestLoop, ValLoop
from torch.nn.modules.batchnorm import BatchNorm2d
from torch.nn.modules.normalization import GroupNorm
from torch.optim.adamw import AdamW

from mmdet.datasets.transforms import (LoadAnnotations, PackDetInputs,
                                       RandomCrop, RandomFlip, Resize)
from mmdet.models import (DINO, ChannelMapper, DetDataPreprocessor, DINOHead,
                          ResNet)
from mmdet.models.losses.focal_loss import FocalLoss
from mmdet.models.losses.iou_loss import GIoULoss
from mmdet.models.losses.smooth_l1_loss import L1Loss
from mmdet.models.task_modules import (BBoxL1Cost, FocalLossCost,
                                       HungarianAssigner, IoUCost)

with read_base():
    from .._base_.datasets.coco_detection import *
    from .._base_.default_runtime import *

model = dict(
    type=DINO,
    num_queries=900,  # num_matching_queries
    with_box_refine=True,
    as_two_stage=True,
    data_preprocessor=dict(
        type=DetDataPreprocessor,
        mean=[123.675, 116.28, 103.53],
        std=[58.395, 57.12, 57.375],
        bgr_to_rgb=True,
        pad_size_divisor=1),
    backbone=dict(
        type=ResNet,
        depth=50,
        num_stages=4,
        out_indices=(1, 2, 3),
        frozen_stages=1,
        norm_cfg=dict(type=BatchNorm2d, requires_grad=False),
        norm_eval=True,
        style='pytorch',
        init_cfg=dict(
            type=PretrainedInit, checkpoint='torchvision://resnet50')),
    neck=dict(
        type=ChannelMapper,
        in_channels=[512, 1024, 2048],
        kernel_size=1,
        out_channels=256,
        act_cfg=None,
        norm_cfg=dict(type=GroupNorm, num_groups=32),
        num_outs=4),
    encoder=dict(
        num_layers=6,
        layer_cfg=dict(
            self_attn_cfg=dict(embed_dims=256, num_levels=4,
                               dropout=0.0),  # 0.1 for DeformDETR
            ffn_cfg=dict(
                embed_dims=256,
                feedforward_channels=2048,  # 1024 for DeformDETR
                ffn_drop=0.0))),  # 0.1 for DeformDETR
    decoder=dict(
        num_layers=6,
        return_intermediate=True,
        layer_cfg=dict(
            self_attn_cfg=dict(embed_dims=256, num_heads=8,
                               dropout=0.0),  # 0.1 for DeformDETR
            cross_attn_cfg=dict(embed_dims=256, num_levels=4,
                                dropout=0.0),  # 0.1 for DeformDETR
            ffn_cfg=dict(
                embed_dims=256,
                feedforward_channels=2048,  # 1024 for DeformDETR
                ffn_drop=0.0)),  # 0.1 for DeformDETR
        post_norm_cfg=None),
    positional_encoding=dict(
        num_feats=128,
        normalize=True,
        offset=0.0,  # -0.5 for DeformDETR
        temperature=20),  # 10000 for DeformDETR
    bbox_head=dict(
        type=DINOHead,
        num_classes=80,
        sync_cls_avg_factor=True,
        loss_cls=dict(
            type=FocalLoss,
            use_sigmoid=True,
            gamma=2.0,
            alpha=0.25,
            loss_weight=1.0),  # 2.0 in DeformDETR
        loss_bbox=dict(type=L1Loss, loss_weight=5.0),
        loss_iou=dict(type=GIoULoss, loss_weight=2.0)),
    dn_cfg=dict(  # TODO: Move to model.train_cfg ?
        label_noise_scale=0.5,
        box_noise_scale=1.0,  # 0.4 for DN-DETR
        group_cfg=dict(dynamic=True, num_groups=None,
                       num_dn_queries=100)),  # TODO: half num_dn_queries
    # training and testing settings
    train_cfg=dict(
        assigner=dict(
            type=HungarianAssigner,
            match_costs=[
                dict(type=FocalLossCost, weight=2.0),
                dict(type=BBoxL1Cost, weight=5.0, box_format='xywh'),
                dict(type=IoUCost, iou_mode='giou', weight=2.0)
            ])),
    test_cfg=dict(max_per_img=300))  # 100 for DeformDETR

# train_pipeline, NOTE the img_scale and the Pad's size_divisor is different
# from the default setting in mmdet.
train_pipeline = [
    dict(type=LoadImageFromFile, backend_args=backend_args),
    dict(type=LoadAnnotations, with_bbox=True),
    dict(type=RandomFlip, prob=0.5),
    dict(
        type=RandomChoice,
        transforms=[
            [
                dict(
                    type=RandomChoiceResize,
                    resize_type=Resize,
                    scales=[(480, 1333), (512, 1333), (544, 1333), (576, 1333),
                            (608, 1333), (640, 1333), (672, 1333), (704, 1333),
                            (736, 1333), (768, 1333), (800, 1333)],
                    keep_ratio=True)
            ],
            [
                dict(
                    type=RandomChoiceResize,
                    resize_type=Resize,
                    # The radio of all image in train dataset < 7
                    # follow the original implement
                    scales=[(400, 4200), (500, 4200), (600, 4200)],
                    keep_ratio=True),
                dict(
                    type=RandomCrop,
                    crop_type='absolute_range',
                    crop_size=(384, 600),
                    allow_negative_crop=True),
                dict(
                    type=RandomChoiceResize,
                    resize_type=Resize,
                    scales=[(480, 1333), (512, 1333), (544, 1333), (576, 1333),
                            (608, 1333), (640, 1333), (672, 1333), (704, 1333),
                            (736, 1333), (768, 1333), (800, 1333)],
                    keep_ratio=True)
            ]
        ]),
    dict(type=PackDetInputs)
]
train_dataloader.update(
    dataset=dict(
        filter_cfg=dict(filter_empty_gt=False), pipeline=train_pipeline))

# optimizer
optim_wrapper = dict(
    type=OptimWrapper,
    optimizer=dict(
        type=AdamW,
        lr=0.0001,  # 0.0002 for DeformDETR
        weight_decay=0.0001),
    clip_grad=dict(max_norm=0.1, norm_type=2),
    paramwise_cfg=dict(custom_keys={'backbone': dict(lr_mult=0.1)})
)  # custom_keys contains sampling_offsets and reference_points in DeformDETR  # noqa

# learning policy
max_epochs = 12
train_cfg = dict(
    type=EpochBasedTrainLoop, max_epochs=max_epochs, val_interval=1)

val_cfg = dict(type=ValLoop)
test_cfg = dict(type=TestLoop)

param_scheduler = [
    dict(
        type=MultiStepLR,
        begin=0,
        end=max_epochs,
        by_epoch=True,
        milestones=[11],
        gamma=0.1)
]

# NOTE: `auto_scale_lr` is for automatically scaling LR,
# USER SHOULD NOT CHANGE ITS VALUES.
# base_batch_size = (8 GPUs) x (2 samples per GPU)
auto_scale_lr = dict(base_batch_size=16)
